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Purpose: Extensive burn injury mainly affects children, and hypermetabolic state can lead to growth delay. This study aimed to investigate bone histopathological and morphometric aspects, collagen fibers network and the immunoexpression of biological markers related to bone development in a young experimental model for extensive burn., Materials and Methods: A total of 28 male Wistar rats were distributed into Control (C) and subjected to scald burn injury (SBI) groups. Sham or injured animals were euthanized 4 or 14 days post-lesion and proximal epiphyses of the femur were submitted to histological, morphometric (thickness epiphyseal plate), and RUNX-2 and receptor activator of nuclear factor kappa- β ligand (RANK-L) immunoexpression methods., Results: Histopathological femoral findings showed delayed appearance of the secondary ossification center in SBI, 14 days post-injury. Collagen fibers 4 days after injury were observed in articular cartilage as a pantographic network with a transversally oriented lozenge-shaped mesh, but this network was thinner in SBI. Fourteen days after the injury, the pantographic network of collagen presented square-shaped mesh in C, but this aspect was changed to a wider mesh in SBI. Morphometric analysis of epiphyseal plate revealed that the SBI group had less thickness than the respective controls (p<0.05). RUNX-2 showed no difference between groups, but RANK-L score was higher in all SBI groups., Conclusions: Extensive burn injury causes delayed bone growth and morphological changes. Alterations in collagen network and enhancement in immunoreactivity of RANK-L result in increased osteoclastogenesis.

Inflammation and oxidative stress occurs in muscle of Duchenne muscular dystrophy (DMD). The relationship between a panel of biomarkers and the DMD outcome is necessary to indicate of disease progression and response to rehabilitation programs. The aim was to analyze the connective tissue of muscle of Mdx mice and immunoexpression of MMP-2, MMP-9, and 8-OHdG, which signalizes oxidative stress related to DNA damage. Biceps brachii of male C57BL/10 and C57BL/10-Dmd mdx mice was submitted to Hematoxylin-Eosin, Sirius red and immunohistochemistry (MMP-2, MMP-9 and 8-OHdG) analysis. Mdx showed focal lesions with intense inflammation and fibrosis related to immunoexpression of MMP-2 and MMP-9, proving the hypothesis that these MMPs are linked to muscular tissue degeneration, which can be regenerated by their inhibition, improving the treatment of DMD carriers. Histopathological findings related to centralized nuclei increase were related to higher 8-OHdG immunomarked nuclei in Mdx, which signalizes oxidative stress associated with DNA damage provoked by DMD. Such result shows that the evaluation of 8-OHdG during the evolution of the disease could be a method to evaluate DMD disease progression., (Copyright © 2019 Elsevier GmbH. All rights reserved.)

Background: In menopause, there is greater cellular exposure to oxidative stress, related to the decreased antioxidative effects of estrogen. These metabolic changes favor the progression of cardiovascular diseases, such as atherosclerosis. Abnormal function of the aorta - the most important artery - is associated with many cardiovascular diseases. Collagen, especially types I and III, is one of the most important aortic wall components and it can be affected by many factors, including menopause. The 8-OHdG is one of the main markers of DNA oxidative damage induced by reactive oxygen species (ROS)., Objective: We aimed to investigate effects of moderate aerobic training on the ascending aorta of LDL-knockout (LDL-KO) and ovariectomized female mice., Methods: A total of 15 C57BL/6 mice and 15 LDL-KO mice were divided into experimental groups. The thickness and volume density of types I and III collagen fibers were performed by morphoquantitative analysis, whereas the MMP-2 and MMP-9 and 8-OHdG were detected by immunohistochemistry and apoptosis was detected by the TUNEL assay. The significance level for all tests was p < 0.05., Results: Exercise causes an increase in the thickness of the aorta in LDL-KO groups, particularly accentuated in the ovariectomized groups. The type I collagen fibers showed an increase in volume density influenced by training in both Control groups and in the LDL-KO group. Type III collagen density decreased in both groups. The MMP-2 showed moderade immunostaining in the tunica media in LDL-KO groups, which did not occur in the control groups and the MMP-9 stained irregularly in all tissues. The marker 8-OhdG was stronger in the exercise training groups. Additionally, the ovariectomy, the exercise training and the LDL-KO treatments increased apoptosis., Conclusion: These results suggest that moderate-intensity aerobic exercise in ovariectomized mice associated to an increase in LDL rate possibly increases oxidative stress and apoptosis induction.